Flexible blade fax



E. NEWNHAM Aug. 6, 1940.

FLEXIBLE BLADE FAN Original Filed Feb. 18, 1956 iii Reissued Aug, 6, 194!) An object of my invention is to provide a flexible blade i'an sive construction is pro 5 PATENT, omcri i 1 rmxmna' we FAN Eugene Newnliam, St.

Knapp-Monarch Company, corporation of Missouri Original No.

Serial No. 64, tion for reissue Janu 250,247

19 Claims.

which simple a d inexpenvided for mount g flexible fan blades relative to a motor shaft or the like.

Still a further object is to. provide a tan structure in which a ca which fan blades p is provided with slots through extend, the inner ends of the fan blades being secured together as by a collar or the like to position the blades radially with respect to the cap A still further object ture especially d blades of rubber o are maintained at the proper pitch angle, al-

ito provide a hub strucesignedfor mounting flexible r similar material, so that they though upon striking an object they can. bend backwardly for the purpose of preventing breakage oi the blades and/or damage to the object.

More particularly it is an object oi my invention to provide a cap moulded or otherwise fixed relative to a hub proper pitch ang may extend, the

and provided with, slots at the le through which the fan blades inner ends of the blades being secured together to r etain them in position relative to the cap against the action of centrifugal force when the cap is rotated;

Still another object is to prov which includes 7 a v ide. a structurecombination of elements including a hub, fan blades, a connector element, and a cap, the blades being readily insertible' simultaneously into slots of the cap during assembly by rotating the blades relative to the cap and thereafter held by the-slots at the proper pitch angle and by the connector element against expulsion by cent ture isv rotated.

With these and rifugal action when the strucvention consistsfin the construction, arrangement and combination of the various parts of the device, whereby the objects contemplated are atta pointed ou accompanying d Figure l is a ined, as h ereinaiter more iully set forth,

t in my-claims, and illustrated in the 'rawing, in which: side elevation of a flexible blade fan embodying my invention.

Figure 2 is an same on the line 2 enlarged sectional view of the of Figure 1; and

Figure 3 is a further enlarged sectionalview on the line 3-4 of Figure 2. r

On the accompanying drawing I have used the reference numeral II to indicate a support in the form of a base for a fan motor l2. Theshatt oi the fan motor is indicated at ll. My improved ian structure comprises a hub H, a cap C and fan blades F.

"ThehubI-Iisbo redasindicated at I! to receive 2,067,410, dated January other objects in view,-

Louis, Mo... alsig'nor to.

St. Louis, Mo a 513, February 18, 1936. Applicaary 10, 1939, Seriai No the shaft 'II, and is permanently mounted on the shaft by a set-screw l6. For aflording access} of axscrew driver to the set screw i6, I provide a notch ll in the cap 0. r The cap C is moulded on one end of the hub-H and has a central boss 20 engaging the hub H. The hub H may beknurled orotherwise roughened to afford a good joint between the hub H The-cap C extends fromthe-boss 20 back over the hub H and is provided with an annular portion 22, which completely surrounds the hub and conceals it. The annular portion 22' is provided with a plurality of slots 2| cut inwardly from the back face or base 26 of the cap C. These slots arearran'ged at the desired pitch angle for the blades F, so as to maintain the blades normally at their pitch angle;

The blades F are of a, mate to normally maintain their pitch angle, yet flexible enough to bend-upon striking an object, so that the blades are not thereby broken and do not injure the object they strike, such as aper son's hand. I have found rubber to'be a -suitable material. This eliminates the necessity .oiv

providing a'shield on the ian. I l

The blades are retained against-outward movement, caused by centrifugal action, by a collar or connector; element 28- having a plurality of counterpart and rotationally spaced arms] The arms 30 may also be arranged at the desired pitch angle, or substantiallyv parallel. to the slots '14, as is obvious in Figurev 2. The arms- 30 are connected as by rivets or thedike 32 to the inner ends of, the blades F. Thus the blades are retained against radial outward movement through the slots 2d upon rotation of the fan.

The hub H is provided with a shoulder 84. The collar 28 is seated against the shoulder and retainedthereagainst by'a lock out 36. A Washer 40 3B is interposed between the lock nut and the collar.

In the mounting oi flexible blades relative to a hub, which of necessity must be rigid, problems are involved which are overcome ina simple manner by the construction I have'devised. My construction is inexpensive and readily assembled The cap (3 may be of any suitable material, .al-

. though ,I prefer. to use bakelite, hard rubber or thelike. The present device-provides a veryso' ruggedly constructed i'an, yet one which has the advantage-oi the flexible blades which require no guard to protect the usenfrom injury upon coming, in contact with the 'rapidly rotating blades 01' the fan. 7

rial sufflciently rigid I I s g 7 21,6 r s changes may be made i'nthe construe; at an angle relative to the axis of rotation of Y tion and arrangement of the of my device said hub.

" without departing fromthe real spirit and purof my invention, and it is my intention to I Q by'my claims any modiiied forms oi structitre or use of mechanical equivalents which may be reasonably included within their scope. I claimas my invention: a g l 11A flexible blade fan comprising a hub havl0 arms arranged at the desired pitch angle, a of single piece blades each formed 01' q suiilciently flexible upon striking an *objot. to bend and oi'itself to l e-assume its original position withoutpermanent distortion,

.1 and rigid that during rotation it will itsjpitch for the me of air delivery,

having their inner ends secured to and soap connected with said hub, capv having slots to receive said blades at points outwardly from their secured inner "ends, said slots being arranged at the desired 'pitch'angle-relative to the axis of rotation of 1 game? v i g inflexible blasiefan comprising a hub; a

2 lurality of blndes-eaohjro med of material suffl x ble an'obiect to bend m me rs assun'ie its original position without permanent distortion; and: suiilciently I [rig d that during will maintain its iipiteh tor the urpose of air. saidblades having their n r end: at'thedcsired PM wi l. hu nd a can. onnec with said hub. said. cap having slots to said I blades at points spaced outwardlr their inner ends, said slots-beingarraruedat the desired pitch angle relative to 18 8b! rot tion ot-the cap, the slots Q1" saldcap opening at one face thereof whereby said, blades b 1 inserted edgewise intoihe'siots' s. A flexible blade .fan comprisinjg allhub, s.

plurality or blades therefrom and} being formedo! material w a hl x ble to bending thereof uponengaging an object during rotation of the fan. il suiliciently. rigid to main sum 1 u 'tain its pitch angle during rototlo i r eil'eeflive ai r delivery, a cap secured to and so hub said slots and'thereby maintained beyond the cap at the desired pitch angle. 8.1 11

cap being ellipsoidal and, of; saldbladea' converging substantially to'a point.

4. a flexible blade'fan a'hub. a ll plurality. of blades therefrom and being formed of material mmcien r flexibl tov permit bending of upon ensur n snhbi'e'ct urin rotation or the tan.'yet suiilcienti rigid. to maintain its pitch angle during ro ation. for elective air 'delivery,'a hollow cap secured to and enclosing said hub -and having slots inwardly from the base thereof arranged at an angle rela- 'tive totheaxis oithe cap, a collar on said hub concealed within said cap, the inner ends ol said blades being secured to said collar at the desired piteb angle and theouter'e'nds thereof extending,

spaced -roidliluy-tl-om said. hub and had relative thereto for determining the pi'tch angle of said blades, said means having slots for receiv- 'in snid blades in contact with an" object, said blades having 'blades oi sufllciently rigid material to normally maintain their pitchQangle for the purpose oi.

said hub and having slots inwardly, the" basethereofarrangedat'an angle relative te'the axisof the cap, said blades einending fromsaid 7 ment. with said"shoulder.'--."

6- In-a device of the class described. a hub; substantially flat bladesoi suillciently rigid'material to normally maintain their pitch angle for, the purpose of-prope ung air, yet suiliciently flexible to permit bending thereof upon coming their inner ends secured to said hub and extending substantially radially from the hub and means also extending from the hub and engaging the blades throughout the width of each at a point radially outwardly from the hub to determine the pitch angle of the blades.

7. In a device of the class described, a hub,

propelling air, yet sufllciently flexible to permit bending thereof upon coming in contact with an object, said blades having their inner ends secured to said hub and extending substantially radially from the hub and means also extending from the hub and; engaging the blades radially. outwardly from the hub to determine thepitch angle of the blades, said means comprising ll cap having slots receiving said blades, said blades filling the slots widthwise. 1 I

8. In a device of the classdescribed, a hub, blades oi' suillciently rigid material to normally maintain their pitch angle for the purpose of propelling air, yet sumciently flexible to permit bending thereof uponiooming in contact with any'obiect, said blades having their inner ends secured tosaid hub and extending substantially radially from the hub and means also extending u from the hub and engaging the blades radially i. outwardly from the hub to determinethe pitch angle or the blades, said means comprisinga cap h'aving its center portion mountedonone I end ofsaid hub and having an outwardly slop- "o ing annular portion provided with slots arranged.

atan angle relative to the axis of rotation of the .cap and receiving said blades. .QJIna device oi the class described. 'a hub.

flexible material to 4g an object, yet suillciently rigid to their piteh angle Q 11 and having blade-m m; t

endsior said blades. being secured? to said blade-Ike and means extending from the. so

hub en aging the blades throughout the entire or determine the pitch angle odthe bladesr '10. In a devise oithe described, a-hub, bladesfsumcienflyflexiblematerial to bend 85 upon an yet sudiciently rigid to normally maintain pitch angle, acollar on said hubs the inner endsoisaid blades beingsecured thereto andmeans the hub and theblades outwardlyfrom on o d collar toaster-nine the or the hubhaviiiga moulder'ssainstwhioh the collar it ss d-eon i-xebuts and a. look. nut o i'j-e msegl-y 5 ii. A ian structure comprising. a hub,

having a, center portion mounted 9 and r said hub and an annular portion and; concealing the hub, said annular portion slots-to receive fan blades 'etkewise. fan blades 7 received'in said slots and means'for inner, ends of said fan blades to said hub.

12. A fan structure comprising a h b. a cap having'a center portion, one. end oi said hub being embedded therein, said cap anjan- .15

nular portion surrounding and concealing the hub, said annular portion having slots to receive fan blades edgewise, fan blades received in said slots and means within said annular portion for connecting said blades together and thereby retaining them against radial outward movement through said slots.

13. In a device of the class described, a hub a hollow cap surrounding'and enclosing said hub, fan blades extending through said cap to the space therewithin and arms on said hub for connecting the inner ends of said blades together to retain them against outward movement relative to said cap upon rotation of the cap.

14. A flexible blade fan comprising a hub, a plurality of fan blades formed of material sufflciently flexible upon striking an object to bend and of themselves to re-assume their original position without permanent distortion and sufflciently rigid that during rotation they will maintain their pitch angle for the purpose of air delivery, said blades being secured flatwise to said hub, and a cap connected with said hub, said cap having slots to receive said blades at points spaced radially from said hub, said slots being arranged at the desired pitch angle relative to the axis of rotation of the cap.

15. A flexible blade fan comprising a hub, a plurality of fan blades radiating therefrom and being formed of material sufliciently flexible to permit bending thereof upon engaging and object during rotation vof the fan, yet sufliciently rigid to maintain their pitch angle during rotation for effective air delivery, a cap surrounding said hub and having slots extending inwardly from the base thereof and arranged at an angle relative to the axis of the cap, a connector element on said hub within said cap, said blades being connected therewith and extending therefrom and through said slots and thereby maintained beyond the cap at the desired pitch angle.

16. A flexible blade fan comprising a hub, a plurality of blades radiating therefrom and being formed of material sufllciently flexible to permit bending thereof upon engaging an object during rotation of the fan, yet sumciently rigid to maintain their pitch angle during rotation for effective air delivery, a hollow cap secured to and surrounding said hub and having slots ex-{ tending inwardly'from the base thereof and arranged at an angle relative to the axis of the cap, a connector element surrounding said. hub and concealed within said cap, said blades being secured to said connector element and the outer ends thereof extending through said slots.

1'7. In an impeller, blades formed of flexible material of generally uniform thickness and similar in size and shape, a forwardly convexed dome coaxial with said blades and having counterpart slots extending forwardly into it from the rear end of the dome, said slots spiralling in the same direction rotationally of said dome and being equal in number to said blades and each blade having a similar portion thereof extending through said slots, a 'hub member coaxial with said dome and means associated with said hub member for anchoring said blades thereto.

0 18. An impeller including in rigid assembly, a plurality of flexible, similarly sized'and shaped and uniformly spaced blades and a central blade connecting element, said blades radiating therefrom, means for concaving each blade forwardly about an axis approximately radially of the axis of said blade connecting element, said means comprising a dome member coaxial with said blade connecting element and provided with curved slots through which the blades respectively extend, each of said slots spiraling in the same direction rotationally of the dome member,

member being coaxial with said dome and insertible therein and having circumferentially spaced parts respectively fastened to said blades, each of said parts of the blade carriermember sloping spirally at a pitch corresponding to that .of one of the slots whereby all of said blades are adapted to be slid simultaneously edg'ewise into said slots by rotating the blade carrying member with respect to the dome.

EUGENE NEWNHAM. 

